Natural swimming hole
Boulder Reservoir
Lake · Colorado
Community-reported spot. Details below are compiled from public sources and are reported to be accurate — always verify locally before visiting.
About this swimming hole
Boulder's plains reservoir with a seasonally lifeguarded swim beach (roughly Memorial Day to Labor Day, 10am-6pm) and mountain views on the horizon. The Boulder Reservoir swim area is the city's official open-water swim, popular with triathletes. Warm, shallow, and family-friendly.
Good to know
| Water type | Lake |
|---|---|
| Water temperature | 75 |
| Depth | designated swim beach |
| Best season | June-September |
| Fees | Day-use fee |
| Reservations required | No |
| Hours | sunrise-sunset |
| Parking | Large lot |
| Amenities | restrooms, picnic tables |
| County | Boulder County |
| Nearest town | Boulder |
| Safety notes | Lifeguards on duty during swim beach hours in season only; no dogs May 15-Labor Day |
Map
Nearby swimming holes
Frequently asked questions
Can you swim in Boulder Reservoir?
Yes — Boulder Reservoir is listed as a natural swimming spot in Colorado. Reported water temperature: 75. Heads-up: Lifeguards on duty during swim beach hours in season only; no dogs May 15-Labor Day. There are rarely lifeguards at natural swimming holes — verify conditions locally before you go.
Does Boulder Reservoir require reservations?
No reservations are required at Boulder Reservoir based on current information — but verify before you go.
Is there a fee to visit Boulder Reservoir?
Reported fee info: Day-use fee. Fees can change — confirm with the official link.
When is the best time to visit Boulder Reservoir?
The best season is typically June-September.